Multi-speed planetary transmission

ABSTRACT

A multi-speed transmission including a plurality of planetary gearsets and a plurality of selective couplers to achieve at least nine forward speed ratios is disclosed. The plurality of planetary gearsets may include a first planetary gearset, a second planetary gearset, a third planetary gearset, and a fourth planetary gearset. The plurality of selective couplers may include a number of clutches and a number of brakes. The multi-speed transmission may have four planetary gearsets and six selective couplers. The six selective couplers may include three clutches and three brakes.

RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application Ser.No. 62/400,943, filed Sep. 28, 2016, titled MULTI-SPEED PLANETARYTRANSMISSION, docket AT-P16004USP1, the entire disclosure of which isexpressly incorporated by reference herein.

FIELD OF THE DISCLOSURE

The present disclosure relates to a multi-speed transmission and inparticular to a multi-speed transmission including a plurality ofplanetary gearsets and a plurality of selective couplers to achieve atleast nine forward speed ratios and at least one reverse speed ratio.

BACKGROUND OF THE DISCLOSURE

Multi-speed transmissions use a plurality of planetary gearsets,selective couplers, interconnectors, and additional elements to achievea plurality of forward and reverse speed ratios. Exemplary multi-speedtransmissions are disclosed in US Published Patent Application No.2016/0047440, Ser. No. 14/457,592, titled MULTI-SPEED TRANSMISSION,filed Aug. 12, 2014, the entire disclosure of which is expresslyincorporated by reference herein.

SUMMARY

The present disclosure provides a multi-speed transmission including aplurality of planetary gearsets and a plurality of selective couplers toachieve at least nine forward speed ratios. The plurality of planetarygearsets may include a first planetary gearset, a second planetarygearset, a third planetary gearset, and a fourth planetary gearset. Theplurality of selective couplers may include a number of clutches and anumber of brakes. In one example, the present disclosure provides amulti-speed transmission having four planetary gearsets and sixselective couplers. The six selective couplers may include threeclutches and three brakes.

In some instances throughout this disclosure and in the claims, numericterminology, such as first, second, third, and fourth, is used inreference to various gearsets, gears, gearset components,interconnectors, selective couplers, and other components. Such use isnot intended to denote an ordering of the components. Rather, numericterminology is used to assist the reader in identifying the componentbeing referenced and should not be narrowly interpreted as providing aspecific order of components. For example, a first planetary gearsetidentified in the drawings may support any one of the plurality ofplanetary gearsets recited in the claims, including the first planetarygearset, the second planetary gearset, the third planetary gearset, andthe fourth planetary gearset, depending on the language of the claims.

According to an exemplary embodiment of the present disclosure, atransmission is provided. The transmission comprising at least onestationary member; an input member; a plurality of planetary gearsetsoperatively coupled to the input member; a plurality of selectivecouplers operatively coupled to the plurality of planetary gearsets; andan output member operatively coupled to the input member through theplurality of planetary gearsets. Each planetary gearset of the pluralityof planetary gearsets includes a sun gear, a plurality of planet gearsoperatively coupled to the sun gear, a planet carrier operativelycoupled to the plurality of planet gears, and a ring gear operativelycoupled to the plurality of planet gears. The plurality of planetarygearsets including a first planetary gearset, a second planetarygearset, a third planetary gearset, and a fourth planetary gearset. Eachof the plurality of selective couplers has an engaged configuration anda disengaged configuration. The plurality of selective couplers includesa first number of clutches and a second number of brakes, the firstnumber being equal to the second number. The input member is fixedlycoupled to the plurality of planetary gearsets through only the sun gearof the first planetary gearset. The output member is fixedly coupled tothe plurality of planetary gearsets through only the ring gear of thefourth planetary gearset.

According to another exemplary embodiment of the present disclosure, atransmission is provided. The transmission comprising at least onestationary member; an input member rotatable relative to the at leastone stationary member; a plurality of planetary gearsets operativelycoupled to the input member; an output member operatively coupled to theinput member through the plurality of planetary gearsets and rotatablerelative to the at least one stationary member; a first interconnectorwhich fixedly couples the third gearset component of the secondplanetary gearset, the second gearset component of the third planetarygearset, and the first gearset component of the fourth planetary gearsettogether; a second interconnector which fixedly couples the secondgearset component of the fourth planetary gearset to the third gearsetcomponent of the first planetary gearset; and a third interconnectorwhich fixedly couples the second gearset component of the secondplanetary gearset to the third gearset component of the third planetarygearset; and a plurality of selective couplers. Each of the plurality ofplanetary gearsets includes a first gearset component, a second gearsetcomponent, and a third gearset component. The plurality of planetarygearsets includes a first planetary gearset, a second planetary gearset,a third planetary gearset, and a fourth planetary gearset. The inputmember is fixedly coupled to the first gearset component of the firstplanetary gearset. The output member is fixedly coupled to the thirdgearset component of the fourth planetary gearset. The plurality ofselective couplers includes a first selective coupler which, whenengaged, fixedly couples the second gearset component of the fourthplanetary gearset and the third gearset component of the first planetarygearset to the at least one stationary member; a second selectivecoupler which, when engaged, fixedly couples the second gearsetcomponent of the second planetary gearset and the third gearsetcomponent of the third planetary gearset to the at least one stationarymember; a third selective coupler which, when engaged, fixedly couplesthe first gearset component of the third planetary gearset to the atleast one stationary member; a fourth selective coupler which, whenengaged, fixedly couples the first gearset component of the secondplanetary gearset to the first gearset component of the first planetarygearset; a fifth selective coupler which, when engaged, fixedly couplesthe second gearset component of the first planetary gearset to the thirdgearset component of the fourth planetary gearset; and a sixth selectivecoupler which, when engaged, fixedly couples the first gearset componentof the second planetary gearset to the second gearset component of thefirst planetary gearset.

BRIEF DESCRIPTION OF THE DRAWINGS

The above-mentioned and other features and advantages of thisdisclosure, and the manner of attaining them, will become more apparentand will be better understood by reference to the following descriptionof exemplary embodiments taken in conjunction with the accompanyingdrawings, wherein:

FIG. 1 is a diagrammatic view of an exemplary multi-speed transmissionincluding four planetary gearsets and six selective couplers; and

FIG. 2 is a truth table illustrating the selective engagement of the sixselective couplers of FIG. 1 to provide ten forward gear or speed ratiosand a reverse gear or speed ratio of the multi-speed transmission ofFIG. 1.

Corresponding reference characters indicate corresponding partsthroughout the several views. The exemplification set out hereinillustrates an exemplary embodiment of the invention and suchexemplification is not to be construed as limiting the scope of theinvention in any manner.

DETAILED DESCRIPTION

For the purposes of promoting an understanding of the principles of thepresent disclosure, reference is now made to the embodiment illustratedin the drawings, which is described below. The embodiment disclosedbelow is not intended to be exhaustive or limit the present disclosureto the precise form disclosed in the following detailed description.Rather, the embodiment is chosen and described so that others skilled inthe art may utilize its teachings. Therefore, no limitation of the scopeof the present disclosure is thereby intended. Corresponding referencecharacters indicate corresponding parts throughout the several views.

In the disclosed transmission embodiment, selective couplers aredisclosed. A selective coupler is a device which may be actuated tofixedly couple two or more components together. A selective couplerfixedly couples two or more components to rotate together as a unit whenthe selective coupler is in an engaged configuration. Further, the twoor more components may be rotatable relative to each other when theselective coupler is in a disengaged configuration. The terms “couples”,“coupled”, “coupler” and variations thereof are used to include botharrangements wherein the two or more components are in direct physicalcontact and arrangements wherein the two or more components are not indirect contact with each other (e.g., the components are “coupled” viaat least a third component), but yet still cooperate or interact witheach other.

A first exemplary selective coupler is a clutch. A clutch couples two ormore rotating components to one another so that the two or more rotatingcomponents rotate together as a unit in an engaged configuration andpermits relative rotation between the two or more rotating components inthe disengaged position. Exemplary clutches may be shiftablefriction-locked multi-disk clutches, shiftable form-locking claw orconical clutches, wet clutches, or any other known form of a clutch.

A second exemplary selective coupler is a brake. A brake couples one ormore rotatable components to a stationary component to hold the one ormore rotatable components stationary relative to the stationarycomponent in the engaged configuration and permits rotation of the oneor more components relative to the stationary component in thedisengaged configuration. Exemplary brakes may be configured asshiftable-friction-locked disk brakes, shiftable friction-locked bandbrakes, shiftable form-locking claw or conical brakes, or any otherknown form of a brake.

Selective couplers may be actively controlled devices or passivedevices. Exemplary actively controlled devices include hydraulicallyactuated clutch or brake elements and electrically actuated clutch orbrake elements. Additional details regarding systems and methods forcontrolling selective couplers are disclosed in the above-incorporatedUS Published Patent Application No. 2016/0047440.

In addition to coupling through selective couplers, various componentsof the disclosed transmission embodiments may be fixedly coupledtogether continuously throughout the operation of the disclosedtransmissions. Components may be fixedly coupled together eitherpermanently or removably. Components may be fixedly coupled togetherthrough spline connections, press fitting, fasteners, welding, machinedor formed functional portions of a unitary piece, or other suitablemethods of connecting components.

The disclosed transmission embodiments include a plurality of planetarygearsets. Each planetary gearset includes at least four components: asun gear; a ring gear; a plurality of planet gears; and a carrier thatis rotatably coupled to and carries the planet gears. In the case of asimple planetary gearset, the teeth of the sun gear are intermeshed withthe teeth of the planet gears which are in turn intermeshed with theteeth of the ring gear. Each of these components may also be referred toas a gearset component. It will be apparent to one of skill in the artthat some planetary gearsets may include further components than thoseexplicitly identified. For example, one or more of the planetarygearsets may include two sets of planet gears. A first set of planetgears may intermesh with the sun gear while the second set of planetgears intermesh with the first set of planet gears and the ring gear.Both sets of planet gears are carried by the planet carrier.

One or more rotating components, such as shafts, drums, and othercomponents, may be collectively referred to as an interconnector whenthe one or more components are fixedly coupled together. Interconnectorsmay further be fixedly coupled to one or more gearset components and/orone or more selective couplers.

An input member of the disclosed transmission embodiments is rotated bya prime mover. Exemplary prime movers include internal combustionengines, electric motors, hybrid power systems, and other suitable powersystems. In one embodiment, the prime mover indirectly rotates the inputmember through a clutch and/or a torque converter. An output member ofthe disclosed transmission embodiments provides rotational power to oneor more working components. Exemplary working components include one ormore drive wheels of a motor vehicle, a power take-off shaft, and othersuitable devices. The output member is rotated based on theinterconnections of the gearset components and the selective couplers ofthe transmission. By changing the interconnections of the gearsetcomponents and the selective couplers, a rotation speed of the outputmember may be varied from a rotation speed of the input member.

The disclosed transmission embodiment is capable of transferring torquefrom the input member to the output member and rotating the outputmember in at least nine forward gear or speed ratios relative to theinput member, illustratively ten forward gear or speed ratios, and onereverse gear or speed ratio wherein the rotation direction of the outputmember is reversed relative to its rotation direction for the at leastnine forward ratios. Exemplary gear ratios that may be obtained usingthe embodiments of the present disclosure are disclosed herein. Ofcourse, other gear ratios are achievable depending on thecharacteristics of the gearsets utilized. Exemplary characteristicsinclude respective gear diameters, the number of gear teeth, and theconfigurations of the various gears.

FIG. 1 is a diagrammatic representation of a multi-speed transmission100. Multi-speed transmission 100 includes an input member 102 and anoutput member 104. Each of input member 102 and output member 104 isrotatable relative to at least one stationary member 106. An exemplaryinput member 102 is an input shaft or other suitable rotatablecomponent. An exemplary output member 104 is an output shaft or othersuitable rotatable component. An exemplary stationary member 106 is ahousing of multi-speed transmission 100. The housing may include severalcomponents coupled together.

Multi-speed transmission 100 includes a plurality of planetary gearsets,illustratively a first planetary gearset 108, a second planetary gearset110, a third planetary gearset 112, and a fourth planetary gearset 114.In one embodiment, additional planetary gearsets may be included.Further, although first planetary gearset 108, second planetary gearset110, third planetary gearset 112, and fourth planetary gearset 114 areillustrated as simple planetary gearsets, it is contemplated thatcompound planetary gearsets may be included in some embodiments.

In one embodiment, multi-speed transmission 100 is arranged asillustrated in FIG. 1, with first planetary gearset 108 positionedbetween a first location or end 116 at which input member 102 entersstationary member 106 and second planetary gearset 110, second planetarygearset 110 is positioned between first planetary gearset 108 and thirdplanetary gearset 112, third planetary gearset 112 is positioned betweensecond planetary gearset 110 and fourth planetary gearset 114, andfourth planetary gearset 114 is positioned between third planetarygearset 112 and a second location or end 118 at which output member 104exits stationary member 106. In alternative embodiments, first planetarygearset 108, second planetary gearset 110, third planetary gearset 112,and fourth planetary gearset 114 are arranged in any order relative tolocation 116 and location 118. In the illustrated embodiment of FIG. 1,each of first planetary gearset 108, second planetary gearset 110, thirdplanetary gearset 112, and fourth planetary gearset 114 are axiallyaligned. In one example, input member 102 and output member 104 are alsoaxially aligned with first planetary gearset 108, second planetarygearset 110, third planetary gearset 112, and fourth planetary gearset114. In alternative embodiments, one or more of input member 102, outputmember 104, first planetary gearset 108, second planetary gearset 110,third planetary gearset 112, and fourth planetary gearset 114 are offsetand not axially aligned with the remainder.

First planetary gearset 108 includes a sun gear 120, a planet carrier122 supporting a plurality of planet gears 124, and a ring gear 126.Second planetary gearset 110 includes a sun gear 130, a planet carrier132 supporting a plurality of planet gears 134, and a ring gear 136.Third planetary gearset 112 includes a sun gear 140, a planet carrier142 supporting a plurality of planet gears 144, and a ring gear 146.Fourth planetary gearset 114 includes a sun gear 150, a planet carrier152 supporting a plurality of planet gears 154, and a ring gear 156.

Multi-speed transmission 100 further includes a plurality of selectivecouplers, illustratively a first selective coupler 162, a secondselective coupler 164, a third selective coupler 166, a fourth selectivecoupler 168, a fifth selective coupler 170, and a sixth selectivecoupler 172. In the illustrated embodiment, first selective coupler 162,second selective coupler 164, and third selective coupler 166 are brakesand fourth selective coupler 168, fifth selective coupler 170, and sixthselective coupler 172 are clutches. The axial locations of the clutchesand brakes relative to the plurality of planetary gearsets may bealtered from the illustrated axial locations.

Multi-speed transmission 100 includes several components that areillustratively shown as being fixedly coupled together. Input member 102is fixedly coupled to sun gear 120 of first planetary gearset 108 andfourth selective coupler 168. Output member 104 is fixedly coupled toring gear 156 of fourth planetary gearset 114 and to fifth selectivecoupler 170. Ring gear 136 of second planetary gearset 110 is fixedlycoupled to planet carrier 142 of third planetary gearset 112 and sungear 150 of fourth planetary gearset 114. Ring gear 126 of firstplanetary gearset 108 is fixedly coupled to planet carrier 152 of fourthplanetary gearset 114 and first selective coupler 162. Planet carrier132 of second planetary gearset 110 is fixedly coupled to ring gear 146of third planetary gearset 112 and second selective coupler 164. Planetcarrier 122 of first planetary gearset 108 is fixedly coupled to fifthselective coupler 170 and sixth selective coupler 172. Sun gear 140 ofthird planetary gearset 112 is fixedly coupled to third selectivecoupler 166. Sun gear 130 of second planetary gearset 110 is fixedlycoupled to fourth selective coupler 168 and to sixth selective coupler172. In alternative embodiments, one or more of the components fixedlycoupled together are selectively coupled together through one or moreselective couplers.

Multi-speed transmission 100 may be described as having eightinterconnectors. Input member 102 is a first interconnector that bothprovides input torque to multi-speed transmission 100 and fixedlycouples sun gear 120 of first planetary gearset 108 to fourth selectivecoupler 168. Output member 104 is a second interconnector that bothprovides output torque from multi-speed transmission 100 and fixedlycouples ring gear 156 of fourth planetary gearset 114 to fifth selectivecoupler 170. A third interconnector 180 fixedly couples ring gear 136 ofsecond planetary gearset 110, planet carrier 142 of third planetarygearset 112, and sun gear 150 of fourth planetary gearset 114 together.A fourth interconnector 182 fixedly couples planet carrier 152 of fourthplanetary gearset 114, ring gear 126 of first planetary gearset 108, andfirst selective coupler 162 together. A fifth interconnector 184 fixedlycouples planet carrier 132 of second planetary gearset 110, ring gear146 of third planetary gearset 112, and second selective coupler 164together. A sixth interconnector 186 fixedly couples planet carrier 122of first planetary gearset 108, fifth selective coupler 170, and sixthselective coupler 172 together. A seventh interconnector 188 fixedlycouples sun gear 140 of third planetary gearset 112 and third selectivecoupler 166 together. An eighth interconnector 190 fixedly couples sungear 130 of second planetary gearset 110, fourth selective coupler 168,and sixth selective coupler 172 together.

Multi-speed transmission 100 further includes several components thatare illustratively shown as being selectively coupled together throughselective couplers. First selective coupler 162, when engaged, fixedlycouples planet carrier 152 of fourth planetary gearset 114 and ring gear126 of first planetary gearset 108 to stationary member 106. When firstselective coupler 162 is disengaged, planet carrier 152 of fourthplanetary gearset 114 and ring gear 126 of first planetary gearset 108may rotate relative to stationary member 106.

Second selective coupler 164, when engaged, fixedly couples planetcarrier 132 of second planetary gearset 110 and ring gear 146 of thirdplanetary gearset 112 to stationary member 106. When second selectivecoupler 164 is disengaged, planet carrier 132 of second planetarygearset 110 and ring gear 146 of third planetary gearset 112 may rotaterelative to stationary member 106.

Third selective coupler 166, when engaged, fixedly couples sun gear 140of third planetary gearset 112 to stationary member 106. When thirdselective coupler 166 is disengaged, sun gear 140 of third planetarygearset 112 may rotate relative to stationary member 106. When secondselective coupler 164 and third selective coupler 166 are both engaged,sun gear 140 and ring gear 146 are fixedly coupled to stationary member106.

Fourth selective coupler 168, when engaged, fixedly couples sun gear 130of second planetary gearset 110 to sun gear 120 of first planetarygearset 108. When fourth selective coupler 168 is disengaged, sun gear130 of second planetary gearset 110 may rotate relative to sun gear 120of first planetary gearset 108.

Fifth selective coupler 170, when engaged, fixedly couples planetcarrier 122 of first planetary gearset 108 to ring gear 156 of fourthplanetary gearset 114. When fifth selective coupler 170 is disengaged,planet carrier 122 of first planetary gearset 108 may rotate relative toring gear 156 of fourth planetary gearset 114.

Sixth selective coupler 172, when engaged, fixedly couples sun gear 130of second planetary gearset 110 to planet carrier 122 of first planetarygearset 108. When sixth selective coupler 172 is disengaged, sun gear130 of second planetary gearset 110 may rotate relative to planetcarrier 122 of first planetary gearset 108.

By engaging various combinations of first selective coupler 162, secondselective coupler 164, third selective coupler 166, fourth selectivecoupler 168, fifth selective coupler 170, and sixth selective coupler172, additional components of multi-speed transmission 100 may befixedly coupled together.

The plurality of planetary gearsets and the plurality of selectivecouplers of multi-speed transmission 100 may be interconnected invarious arrangements to provide torque from input member 102 to outputmember 104 in at least nine forward gear or speed ratios and one reversegear or speed ratio. Referring to FIG. 2, an exemplary truth table 200is shown that provides the state of each of first selective coupler 162,second selective coupler 164, third selective coupler 166, fourthselective coupler 168, fifth selective coupler 170, and sixth selectivecoupler 172 for ten different forward gear or speed ratios and onereverse gear or speed ratio. Each row corresponds to a giveninterconnection arrangement for transmission 100. The first columnprovides the gear range (reverse and 1^(st)-10^(th) forward gears). Thesecond column provides the gear ratio between the input member 102 andthe output member 104. The third column provides the gear step. The sixrightmost columns illustrate which ones of the selective couplers162-172 are engaged (“1” indicates engaged) and which ones of selectivecouplers 162-172 are disengaged (“(blank)” indicates disengaged). FIG. 2is only one example of any number of truth tables possible for achievingat least nine forward ratios and one reverse ratio.

In the example of FIG. 2, the illustrated reverse ratio (Rev) isachieved by having first selective coupler 162, third selective coupler166, and fourth selective coupler 168 in an engaged configuration andsecond selective coupler 164, fifth selective coupler 170, and sixthselective coupler 172 in a disengaged configuration.

In one embodiment, to place multi-speed transmission 100 in neutral(Neu), all of first selective coupler 162, second selective coupler 164,third selective coupler 166, fourth selective coupler 168, fifthselective coupler 170, and sixth selective coupler 172 are in thedisengaged configuration. One or more of first selective coupler 162,second selective coupler 164, third selective coupler 166, fourthselective coupler 168, fifth selective coupler 170, and sixth selectivecoupler 172 may remain engaged in neutral (Neu) as long as thecombination of first selective coupler 162, second selective coupler164, third selective coupler 166, fourth selective coupler 168, fifthselective coupler 170, and sixth selective coupler 172 does not transmittorque from input member 102 to output member 104.

A first forward ratio (shown as 1st) in truth table 200 of FIG. 2 isachieved by having first selective coupler 162, second selective coupler164, and fourth selective coupler 168 in an engaged configuration andthird selective coupler 166, fifth selective coupler 170, and sixthselective coupler 172 in a disengaged configuration.

A second or subsequent forward ratio (shown as 2nd) in truth table 200of FIG. 2 is achieved by having first selective coupler 162, fourthselective coupler 168, and fifth selective coupler 170 in an engagedconfiguration and second selective coupler 164, third selective coupler166, and sixth selective coupler 172 in a disengaged configuration.Therefore, when transitioning between the first forward ratio and thesecond forward ratio, second selective coupler 164 is placed in thedisengaged configuration and fifth selective coupler 170 is placed inthe engaged configuration.

A third or subsequent forward ratio (shown as 3rd) in truth table 200 ofFIG. 2 is achieved by having second selective coupler 164, fourthselective coupler 168, and fifth selective coupler 170 in an engagedconfiguration and first selective coupler 162, third selective coupler166, and sixth selective coupler 172 in a disengaged configuration.Therefore, when transitioning between the second forward ratio and thethird forward ratio, first selective coupler 162 is placed in thedisengaged configuration and second selective coupler 164 is placed inthe engaged configuration.

A fourth or subsequent forward ratio (shown as 4th) in truth table 200of FIG. 2 is achieved by having second selective coupler 164, fifthselective coupler 170, and sixth selective coupler 172 in an engagedconfiguration and first selective coupler 162, third selective coupler166, fourth selective coupler 168 in a disengaged configuration.Therefore, when transitioning between the third forward ratio and thefourth forward ratio, fourth selective coupler 168 is placed in thedisengaged configuration and sixth selective coupler 172 is placed inthe engaged configuration.

A fifth or subsequent forward ratio (shown as 5th) in truth table 200 ofFIG. 2 is achieved by having second selective coupler 164, thirdselective coupler 166, and fifth selective coupler 170 in an engagedconfiguration and first selective coupler 162, fourth selective coupler168, and sixth selective coupler 172 in a disengaged configuration.Therefore, when transitioning between the fourth forward ratio and thefifth forward ratio, sixth selective coupler 172 is placed in thedisengaged configuration and third selective coupler 166 is placed inthe engaged configuration.

A sixth or subsequent forward ratio (shown as 6th) in truth table 200 ofFIG. 2 is achieved by having third selective coupler 166, fifthselective coupler 170, and sixth selective coupler 172 in an engagedconfiguration and first selective coupler 162, second selective coupler164, and fourth selective coupler 168 in a disengaged configuration.Therefore, when transitioning between the fifth forward ratio and thesixth forward ratio, second selective coupler 164 is placed in thedisengaged configuration and sixth selective coupler 172 is placed inthe engaged configuration.

A seventh or subsequent forward ratio (shown as 7th) in truth table 200of FIG. 2 is achieved by having third selective coupler 166, fourthselective coupler 168, and fifth selective coupler 170 in an engagedconfiguration and first selective coupler 162, second selective coupler164, and sixth selective coupler 172 in a disengaged configuration.Therefore, when transitioning between the sixth forward ratio and theseventh forward ratio, sixth selective coupler 172 is placed in thedisengaged configuration and fourth selective coupler 168 is placed inthe engaged configuration.

An eighth or subsequent forward ratio (shown as 8th) in truth table 200of FIG. 2 is achieved by having fourth selective coupler 168, fifthselective coupler 170, and sixth selective coupler 172 in an engagedconfiguration and first selective coupler 162, second selective coupler164, and third selective coupler 166 in a disengaged configuration.Therefore, when transitioning between the seventh forward ratio and theeighth forward ratio, third selective coupler 166 is placed in thedisengaged configuration and sixth selective coupler 172 is placed inthe engaged configuration.

A ninth or subsequent forward ratio (shown as 9th) in truth table 200 ofFIG. 2 is achieved by having third selective coupler 166, fourthselective coupler 168, and sixth selective coupler 172 in an engagedconfiguration and first selective coupler 162, second selective coupler164, and fifth selective coupler 170 in a disengaged configuration.Therefore, when transitioning between the eighth forward ratio and theninth forward ratio, fifth selective coupler 170 is placed in thedisengaged configuration and third selective coupler 166 is placed inthe engaged configuration.

A tenth or subsequent forward ratio (shown as 10th) in truth table 200of FIG. 2 is achieved by having second selective coupler 164, fourthselective coupler 168, and sixth selective coupler 172 in an engagedconfiguration and first selective coupler 162, third selective coupler166, and fifth selective coupler 170 in a disengaged configuration.Therefore, when transitioning between the ninth forward ratio and thetenth forward ratio, third selective coupler 166 is placed in thedisengaged configuration and second selective coupler 164 is placed inthe engaged configuration.

The present disclosure contemplates that downshifts follow the reversesequence of the corresponding upshift (as described above). Further,several power-on skip-shifts that are single-transition are possible(e.g. from 1^(st) up to 3^(rd), from 3^(rd) down to 1^(st), from 3^(rd)up to 5^(th), and from 5^(th) down to 3^(rd)).

In the illustrated embodiments, various combinations of three of theavailable selective couplers are engaged for each of the illustratedforward speed ratios and reverse speed ratios. Additional forward speedratios and reverse speed ratios are possible based on other combinationsof engaged selective couplers. Although in the illustrated embodiments,each forward speed ratio and reverse speed ratio has three of theavailable selective couplers engaged, it is contemplated that less thanthree and more than three selective couplers may be engaged at the sametime.

While this invention has been described as having exemplary designs, thepresent invention can be further modified within the spirit and scope ofthis disclosure. This application is therefore intended to cover anyvariations, uses, or adaptations of the invention using its generalprinciples. Further, this application is intended to cover suchdepartures from the present disclosure as come within known or customarypractice in the art to which this invention pertains and which fallwithin the limits of the appended claims.

What is claimed is:
 1. A transmission comprising: at least onestationary member; an input member; a plurality of planetary gearsetsoperatively coupled to the input member, each planetary gearset of theplurality of planetary gearsets including a sun gear, a plurality ofplanet gears operatively coupled to the sun gear, a planet carrieroperatively coupled to the plurality of planet gears, and a ring gearoperatively coupled to the plurality of planet gears, the plurality ofplanetary gearsets including a first planetary gearset, a secondplanetary gearset, a third planetary gearset, and a fourth planetarygearset; a plurality of selective couplers operatively coupled to theplurality of planetary gearsets, each of the plurality of selectivecouplers having an engaged configuration and a disengaged configuration,the plurality of selective couplers including a first number of clutchesand a second number of brakes, the first number being equal to thesecond number; and an output member operatively coupled to the inputmember through the plurality of planetary gearsets, wherein the inputmember is fixedly coupled to the plurality of planetary gearsets throughonly the sun gear of the first planetary gearset and the output memberis fixedly coupled to the plurality of planetary gearsets through onlythe ring gear of the fourth planetary gearset.
 2. The transmission ofclaim 1, wherein the plurality of selective couplers includes a firstclutch, a second clutch, a third clutch, a first brake fixedly coupledto the at least one stationary member, a second brake fixedly coupled tothe at least one stationary member, and a third brake fixedly coupled tothe at least one stationary member.
 3. The transmission of claim 2,further comprising: a first interconnector which fixedly couples thering gear of the second planetary gearset, the planet carrier of thethird planetary gearset, and the sun gear of the fourth planetarygearset together; a second interconnector which fixedly couples theplanet carrier of the fourth planetary gearset to the ring gear of thefirst planetary gearset; and a third interconnector which fixedlycouples the planet carrier of the second planetary gearset to the ringgear of the third planetary gearset.
 4. The transmission of claim 3,wherein the first brake, when engaged, fixedly couples the planetcarrier of the fourth planetary gearset and the ring gear of the firstplanetary gearset to the at least one stationary member; the secondbrake, when engaged, fixedly couples the ring gear of the thirdplanetary gearset and the planet carrier of the second planetary gearsetto the at least one stationary member; the third brake, when engaged,fixedly couples the sun gear of the third planetary gearset to the atleast one stationary member; the first clutch, when engaged, fixedlycouples the sun gear of the second planetary gearset to the sun gear ofthe first planetary gearset; the second clutch, when engaged, fixedlycouples the planet carrier of the first planetary gearset to the ringgear of the fourth planetary gearset; and the third clutch, whenengaged, fixedly couples the sun gear of the second planetary gearset tothe planet carrier of the first planetary gearset.
 5. The transmissionof claim 4, wherein the first clutch, when engaged, further fixedlycouples the input member to the sun gear of the second planetarygearset.
 6. The transmission of claim 4, wherein the second brake andthe third brake, when both are engaged, lock the sun gear of the thirdplanetary gearset and the ring gear of the third planetary gearsettogether.
 7. The transmission of claim 4, wherein each of the firstplanetary gearset, the second planetary gearset, the third planetarygearset, and the fourth planetary gearset is a simple planetary gearset.8. The transmission of claim 7, wherein the at least one stationarymember includes a housing, the housing having a first end and a secondend, wherein the input member is accessible proximate the first end ofthe housing; the output member is accessible proximate the second end ofthe housing; the first planetary gearset is positioned between the firstend of the housing and the second planetary gearset; the secondplanetary gearset is positioned between the first planetary gearset andthe third planetary gearset; the third planetary gearset is positionedbetween the second planetary gearset and the fourth planetary gearset;and the fourth planetary gearset is positioned between the thirdplanetary gearset and the second end of the housing.
 9. The transmissionof claim 8, wherein the plurality of selective couplers are selectivelyengaged in a plurality of combinations to establish at least nineforward speed ratios and at least one reverse speed ratio between theinput member and the output member, each of the plurality ofcombinations having at least three of the plurality of selectivecouplers engaged.
 10. A transmission comprising: at least one stationarymember; an input member rotatable relative to the at least onestationary member; a plurality of planetary gearsets operatively coupledto the input member, each of the plurality of planetary gearsetsincluding a first gearset component, a second gearset component, and athird gearset component, the plurality of planetary gearsets including afirst planetary gearset, a second planetary gearset, a third planetarygearset, and a fourth planetary gearset, the input member is fixedlycoupled to the first gearset component of the first planetary gearset;an output member operatively coupled to the input member through theplurality of planetary gearsets and rotatable relative to the at leastone stationary member, the output member is fixedly coupled to the thirdgearset component of the fourth planetary gearset; a firstinterconnector which fixedly couples the third gearset component of thesecond planetary gearset, the second gearset component of the thirdplanetary gearset, and the first gearset component of the fourthplanetary gearset together; a second interconnector which fixedlycouples the second gearset component of the fourth planetary gearset tothe third gearset component of the first planetary gearset; and a thirdinterconnector which fixedly couples the second gearset component of thesecond planetary gearset to the third gearset component of the thirdplanetary gearset; and a plurality of selective couplers, wherein theplurality of selective couplers includes: a first selective couplerwhich, when engaged, fixedly couples the second gearset component of thefourth planetary gearset and the third gearset component of the firstplanetary gearset to the at least one stationary member; a secondselective coupler which, when engaged, fixedly couples the secondgearset component of the second planetary gearset and the third gearsetcomponent of the third planetary gearset to the at least one stationarymember; a third selective coupler which, when engaged, fixedly couplesthe first gearset component of the third planetary gearset to the atleast one stationary member; a fourth selective coupler which, whenengaged, fixedly couples the first gearset component of the secondplanetary gearset to the first gearset component of the first planetarygearset; a fifth selective coupler which, when engaged, fixedly couplesthe second gearset component of the first planetary gearset to the thirdgearset component of the fourth planetary gearset; and a sixth selectivecoupler which, when engaged, fixedly couples the first gearset componentof the second planetary gearset to the second gearset component of thefirst planetary gearset.
 11. The transmission of claim 10, wherein eachof the first planetary gearset, the second planetary gearset, the thirdplanetary gearset, and the fourth planetary gearset is a simpleplanetary gearset.
 12. The transmission of claim 11, wherein the firstgearset component of the first planetary gearset is a first sun gear,the first gearset component of the second planetary gearset is a secondsun gear, the first gearset component of the third planetary gearset isa third sun gear, the first gearset component of the fourth planetarygearset is a fourth sun gear, the second gearset component of the firstplanetary gearset is a first planet carrier, the second gearsetcomponent of the second planetary gearset is a second planet carrier,the second gearset component of the third planetary gearset is a thirdplanet carrier, the second gearset component of the fourth planetarygearset is a fourth planet carrier, the third gearset component of thefirst planetary gearset is a first ring gear, the third gearsetcomponent of the second planetary gearset is a second ring gear, thethird gearset component of the third planetary gearset is a third ringgear, and the third gearset component of the fourth planetary gearset isa fourth ring gear.
 13. The transmission of claim 10, wherein the atleast one stationary member includes a housing, the housing having afirst end and a second end, wherein the input member is accessibleproximate the first end of the housing; the output member is accessibleproximate the second end of the housing; the first planetary gearset ispositioned between the first end of the housing and the second planetarygearset; the second planetary gearset is positioned between the firstplanetary gearset and the third planetary gearset; the third planetarygearset is positioned between the second planetary gearset and thefourth planetary gearset; and the fourth planetary gearset is positionedbetween the third planetary gearset and the second end of the housing.14. The transmission of claim 10, wherein the fourth selective member,when engaged, further fixedly couples the input member to the firstgearset component of the second planetary gearset.
 15. The transmissionof claim 10, wherein the second selective coupler and the thirdselective coupler, when both engaged, lock the first gearset componentof the third planetary gearset and the third gearset component of thethird planetary gearset together.
 16. The transmission of claim 10,wherein the plurality of selective couplers are selectively engaged in aplurality of combinations to establish at least nine forward speedratios and at least one reverse speed ratio between the input member andthe output member, each of the plurality of combinations having at leastthree of the plurality of selective couplers engaged.